JPH06507353A - Improved printing apparatus and method - Google Patents

Abstract

Printing apparatus has at least one print station including a blanket cylinder in rolling contact with an impression cylinder, a print cylinder for supporting a lithographic plate, the plate cylinder being in rolling contact with the blanket cylinder, at least one discharge source for applying an image to a plate supported by the plate cylinder, and a motor for moving the energy source relative to the plate cylinder so that when the plate cylinder is rotated, the discharge source scans a raster on the surface of the plate supported by the plate cylinder. The apparatus may be configured as an in-line or central-impression type press. A controller responsive to picture signals representing an original document repeatedly actuates each discharge source momentarily during the scan thereof so that the discharge source forms on the plate surface an image comprised of dots corresponding to the original document. The controller includes a dot-position look-up table for storing the x and y coordinates of substantially all dot positions on the plate and is arranged to actuate each energy source to form image dots at selected ones of the dot positions when said picture signals are present. The apparatus also includes provision for regulating the ink applied to the plate at each print station.

Description

[Detailed description of the invention] Improved printing apparatus and method Related applications This application is filed under U.S. Patent Application No. 077234, now U.S. Patent No. 4,911,075. No. 07/413,172, a continuation-in-part of No. 475 (in its entirety) (incorporated herein by reference) It is.

Background of the invention A-Moxibustion and Weifang M The present invention relates to a printing apparatus and method, and more particularly to a printing apparatus and method using digital spark discharge recording technology. The present invention relates to an improved apparatus for printing monochrome or multicolor prints.

B-Used rice handling technique Ω return Traditional techniques for introducing printed images onto recording materials include letterpress printing, Includes labia printing, offset lithography, etc. these All printing methods involve transferring ink into a pattern of images , a plate usually loaded onto the plate cylinder of a rotary press for efficiency Requires.

In letterpress printing, an image pattern is the shape of a raised area on a plate. This area receives ink and transfers it onto the recording medium by stamping. do. Gravure printing plates, by contrast, contain a series of wells or depressions. This receives the ink and deposits it onto the recording medium. Remove excess ink from the printer. by a doctor blade or other instrument prior to contact between the rate and the recording medium. must be removed from the plate.

In offset lithography, the image is printed on a plate or mat. A pattern consisting of ink-receptive (oleophilic) and ink-repellent (oleophobic) surface areas. It exists as. In dry printing systems, the plates are simply inked and the image is transferred onto the recording medium. Plate first, then blanket Contact is made with a compliant intermediate surface called a cylinder, which in turn , applying the image to paper or other reproduction media. Typical rotary press system odor In this case, the recording medium is fixed to the image cylinder, and the image cylinder covers it with a blanket. contact with the cylinder.

In wet lithographic printing systems, the non-image areas are hydrophilic and do not contain the required ink. Moisturizing (or "squirting") a solution onto the plate prior to inking provided by first applying the . Squirt solution is ink in non-image area , but does not affect the lipophilicity of the image area.

Plates for offset printing are usually produced photographically. typical negative In the working subtractive method, the original document is photographed and a photographic negative is produced. will be accomplished. This negative shows a water-receptive oxidized surface coated with a photopolymer. Placed on an aluminum plate with a surface. Rays of light and other radiation through the negative When exposed to radiation, the area of the coating that received the radiation (the dark part of the original or (corresponding to the printed area) hardens to a durable oleophilic state.

This plate is then subjected to a development process to remove the uncured areas of the coating (i.e. radiation (corresponding to non-image or background areas of the original) that have not received a The uncured regions become oleophobic and/or hydrophilic.

When a printing press prints in more than one color, it prints a separate stamp for each color. printing plates are required, and each such plate typically has a photographically created. In addition to preparing appropriate plates for different colors. The operator must then properly load the plate onto the plate cylinder of the press. You must also adjust the position of the cylinders so that they are printed by different cylinders. Color components must be matched in the print. specific on the printing press Each set of cylinders associated with a color is typically called a printing station.

In most conventional printing presses, the printing stations are linear, or "inline". are arranged in a ``main'' configuration. Each such station typically includes an impression (image). compression cylinder, blanket cylinder, plate cylinder, and the necessary ink (and water in wet systems) assemblies. Record The recording medium is sequentially transferred between print stations in a consistent manner, and each station run is applies different colored inks to the media to produce a composite multicolor image.

No. 4,936,211 (owned by the same assignee as the present invention and whose (the contents of which are hereby incorporated by reference) Another configuration is to transport a sheet of recording media past each printing station. It relies on a central impression cylinder that mechanically transports the media to each printing station. This eliminates the need for transfer to

In both types of printing presses, the recording medium is the cut sheet that is transported to the printing station. , or in the form of a continuous "web" of material. on the printing press The number of printing stations depends on the type of document being printed. documents For printing large quantities of simple black and white line art, use a single printing station. is probably sufficient. Achieve full tonal representation of more complex monochrome images In order to applications apply the same color or shade with different densities.

Full-color printing presses apply ink according to a selected color model, but most commonly The standard ones are based on cyan, magenta, yellow, and black (rCMYKJ model). It is. Therefore, CMYK models require a minimum of four printing stations. , more is needed if you are trying to emphasize a particular color. printing press prints Separate stations for applying spot lacquer to different parts of the document It may also include one or more steps for reversing the recording medium to obtain double-sided printing. It may also feature more "back printing" assemblies.

Both the plate making and ink transfer stages of printing involve a number of difficulties.

The photographic process used to produce conventional plates is time consuming and requires suitable equipment and equipment to carry out the necessary chemical processes. This program To avoid the process, those skilled in the art have have developed alternative methods, some of which can be used onboard. can. In these systems, digitally controlled devices Improve the ink receptivity of the blank plate with a pattern representing the image to be printed. change. Such imaging devices include one or more lasers. or a pulsed source of electromagnetic radiation produced by a non-laser source, which Creates a chemical change in the ranks (thereby eliminating the need for photographic negatives).

Alternatively, an ink-repellent or ink-accepting spot can be applied directly onto the plate blank. It also includes inkjet devices that make the spark discharge device In some cases, the electrodes in contact with or in close proximity to the plate blank are electrically Generates a spark to physically change the topology of the plate blank, thereby This results in "dots". Collectively, the dots form the desired image.

These digital plate making techniques eliminate the flaws associated with more traditional methods. Although many of the conditions have been alleviated, they are not without their own inherent drawbacks.

Such drawbacks are discussed in U.S. Pat. No. 4,911,075 (by the same assignee as the present invention). , the contents of which are incorporated herein by reference. ).

Printing machines also provide alignment between the images applied by the various printing stations. Mechanical assemblies must be provided for maintenance and modification. inline In the case of printing presses, it is necessary to ensure consistent positioning between printing stations. For this purpose, highly accurate paper feed and paper advance mechanisms and precision gear mechanisms can be used. is necessary.

This printing machine also requires To maintain proper rotational, axial, and skew unidirectional phasing, allows to correct misalignment by adjusting the relative position of the target cylinders such positioning corrections must be consistent with the misalignment. This is to correct.

If plates are imaged on-machine, mechanical Although the difficulty has been improved, it has not been eliminated.

In this case, the finished plate may have been improperly installed onto the plate cylinder. Possible positioning errors are effectively overcome. However, multi-station In modern printing presses, both the plate imaging stage and the printing stage , it becomes necessary to maintain alignment between the plate cylinders. i.e. coherent To maintain plate orientation, the print station must align the inks with each other. must be applied to each of the individual plate imaging systems as well. Each has its own plate cylinder (holds the plate being imaged) and must be harmonized both with and among each other.

The ink flow at each printing station must also be precisely regulated and address differences in ink density and produce the desired color correction on the final print. It must remain adjustable so that the U.S. Patent No. 4,058,058 As discussed in It can be equipped with a number of electrically controlled ink adjustment screws or keys. , so that the ink ejectors at each print station The amount of ink applied to the plate cylinder can be adjusted. this These regulators can be operated manually or, to some extent, with the aid of computer equipment. can be controlled.

For example, in some publishing systems, pages are prepared from each full-scale model. The resulting color separations are scanned and digitally stored as proofs. Printed by printing machine The resulting hardcopy is also scanned and compared digitally with the full-size model proof. to determine the necessary ink control adjustments. Therefore, at present, the ink regulator The operator must use judgment that requires time and/or skill to determine the settings for the must be used.

Description of the invention A.1 drunkenness The present invention provides an electronic method, preferably on-board, of one or more glue rough plates. imaging and printing with such plates on various types of printing presses. It consists of a number of interrelated and cooperative components that make it easy to use. Main departure Maintains alignment and alignment of multiple imaged plates and Eliminate or at least reduce the need for the pelleter to manually adjust ink settings. mechanical and electrical structures to enable feedback control of ink regulation. Contains components.

The printing device of the present invention may be an in-line printing press, a central impression printing press, or any other operable printing device. Can be configured as a flexible lithographic design and can be printed in monochrome or color Designed to receive electronic signals representing decomposed images and display them control the imaging device using the signals of the image on the plate blank. is generated. Plate blanks are produced on-machine, which ultimately receives ink and Image is placed on the plate cylinder that transfers the image to the blanket cylinder. imaging or off-board on a separate imaging assembly can do. The recording medium can be fed to the printing machine in cut sheets or webs. , paper, film, metal foil, or a composite of two or more of these (e.g. (a film laminated on paper).

Electronic imaging assembly(s) can be any of several types of technology. However, the basic conditions for digital operation and control are It is ease of familiarity. Suitable techniques include laser and non-laser pulses of electromagnetic radiation. source, electron beam scanning device, inkjet device, and spark discharge imaging device All of these are technically well characterized. each The imaging assembly is the original document to be printed by a specific printing station. Responsive to input image signals representing each of the color components of the document or picture.

Preferred imaging systems of the invention include high voltage, non-contact spark discharge or plasma 4,911,075, granted in US Pat. No. 4,911,075. Patent Application No. 071554089 (owned by the same applicant as the present invention) (the contents of which are hereby incorporated by reference); and Patent Application No. US9010 filed with the United States Patent Application Office on September 28, 1990 5546 entitled “Plasma Jet Imaging Apparatus and Method” PCT application (also owned by the same applicant as the present invention and whose contents are (herein incorporated by reference) .

The present invention addresses alignment errors in several ways. Onboard imaging is that Alignment resulting from incorrect positioning of the printing plate to itself, plate cylinder, L Eliminate errors. This onboard configuration also changes the relative phase of the plate cylinders, or By electronic control of the timing of the image signals applied to the imaging device, Periodic alignment errors are eliminated by ensuring that the image phase remains the same. Make corrections easy.

We have also determined the coverage percentage and/or flash for a particular key. Automatically set and adjust ink adjustment mechanism based on densitometer output It uses an electronic controller. The ink settings provided by the controller are Of course, manual settings can help.

The operation of the equipment is directed by a central computer, which also and can be programmed to provide pre-print functions such as rask image processing.

B. Land blood Q disaster single μ Eiho The foregoing description refers to the following detailed description of the invention in conjunction with the accompanying drawings. will be more easily understood. In the accompanying drawings, FIG. 1 depicts features of the invention. 1 is a schematic side elevational view of an offset color printing press with Figure 2 is a diagram of a test print used to align the printing press and calibrate the colors. be.

C0-like mouth 1.Formation For ease of explanation, as integrated within a conventional inline printing machine. , describes exemplary embodiments of the invention. However, the basic Features also include the central image printing press, such as that described in U.S. Pat. No. 4,936,211. It may also be used in other direct or offset printing machine configurations. It must be understood that

Referring first to FIG. 1, this is a side elevation of an embodiment of an in-line printing press of the present invention. FIG. 3 includes cutaway cross-sections of two printing towers. This printing press is a series of four printing station or tower 15a.

15b, 15c and 15d, each of which applies ink or Contains the equipment necessary to apply the lacquer (described in more detail below). four Although printing stations are shown, depending on the nature of the printing to be performed, conventional of printing presses with a minimum of 1 and a maximum of 10 or more such stations It should be understood that this can include

The individual sheets of recording medium are delivered to the printing station, which is located on the right side of the printing press as seen in Figure 1. It is supplied from the tray 17. A conventional handling mechanism (not shown) remove the sheet from the tray 17 and transport it to the first printing station 15a, There, the sheet is wrapped onto an image cylinder and inked.

The sheet is then stripped from this impression cylinder and transferred to a second printing station 1. 5b, and similar operations are performed there. handling machine The system ensures consistency and alignment of the media as it is transported across the press. It is used to pull sheets between print stations for double-sided printing. It may include repeated "back printing" assemblies.

The cutaway section in FIG. 1 shows two representative printing stations 15C and 15d. Shows the components. Station 15d configured for dry printing includes a series of Ink tray 20 that transfers ink through rollers 22 and automatic ink flow means for controlling the amount and distribution of the ink electronically; includes an ink jetting assembly 19. The roller 22 transfers the ink to the plate cylinder. 24d, and this cylinder is replaced by a blanket cylinder 26 of the same diameter. Make surface contact with d. The blanket cylinder then in turn prints into the image cylinder 28. is in surface contact with d. The printing station is also dotted at reference number 30d. It includes a controller, indicated by lines, which monitors the angular position of plate cylinder 24d. monitor and also provide ink control signals to the ink ejection assembly 19.

A suitable controller design is entitled "Controller for Spark Discharge Imaging" Co-pending attorney document number 15353-28 filed at the same time as this application. United States Patent Application, the entire contents of which are hereby incorporated by reference ), but for purposes here, the controller The camera can be any suitable angular positioning and monitoring system. .

The printing press also includes a suitable feeding device (instead of tray 17) on the uptake side of the printing press. The web of recording media can be imprinted by adding a complementary capture device on the It can also be configured to perform printing.

Printing station 15c is configured for wet printing. In actual implementation In some cases, both wet and dry printing stations can be run in the same press. Their use is rare, and both types are shown in Figure 1 for illustrative purposes only. It's for a reason. Printing station 15c has all the features of printing station 15d. and a water source 34 that supplies water to a water tray 36. Ru. A series of humidifying rollers 37 transfer water from the water tray 36 to the plate cylinder 24c. Transfer. For this station, controller 30c controls water and ink. The administration of both is regulated.

Preferably, the printing station includes on-press images indicated by reference numerals 42c and 42d. This feature is required in all aspects of the invention. That doesn't mean it's true. The imaging system will be detailed later.

The printing press also includes a computer, indicated schematically by the reference numeral 40, which page data and control signals to controllers 30a, 30b, 30c and 30d. Forward. Connections between the computer 40 and the controller are made using appropriate cables. Therefore, it is brought about. The printing press receives digital signals supplied by computer 40. , this signal represents the original document or image.

Computer 40 includes a central processing unit (C) that stores, retrieves, and manipulates data. PU) 44 and a cathode ray tube (CRT) or other suitable device for communicating with the operator. A display 46 and a keyboard for operator input of data and control commands. It consists of 48. The computer 40 can be a single machine or can be used for parallel processing. A set of systems configured to divide the workload and increase effective processing speed. It can consist of a processor. In case of a single machine, the central processing unit Create an architecture equivalent to multiple processors by increasing the number of be able to.

The operator uses the keyboard 48 to image the printing plate on-machine. instructions, alignment information, and/or press controls such as ink flow regulation, number of copies, etc. You can enter commands related to. In addition, as described below, computer The printer 40 allows an operator to input image and text data in an output-ready format. Some "pre-print" functionality may be provided to allow processing. C.P. U44 typically holds large amounts of data associated with digitized images one or more mass storage devices, such as disk or tape drivers, to storage devices.

2 Plate and plate imaging As mentioned above, when used on the machine A number of imaging techniques can be adapted to achieve this goal. Preferences of the present invention A good imaging system is the spark discharge or plasma discharge device mentioned above; These are more fully described in the patents and patent applications cited above. Basic includes an input image signal and accompanying image data provided by computer 40. High voltage pulses with precisely controlled voltage and current profiles depending on the is applied to one or more electrodes or plasma jet sources and directed against the plate. to create a precisely positioned and defined arc or plasma jet discharge . These electrical discharges physically deform selected locations or areas of the plate surface, causing them to be receptive or non-receptive to ink and/or water.

The imaging system is preferably implemented as a scanner or plotter, and These writing heads are positioned above and at a small distance from the working surface of the plate. relative to the plate to collectively scan a raster on the plate surface. It consists of one or more moving electrodes or plasma jet sources. write In order to achieve the required relative movement between the head and the cylindrical plate, the plate around its axis and move the write head parallel to this axis of rotation to Scan the plate in the circumferential direction so that the image of the plate grows in the axial direction. Can be done. Alternatively, the writing head can be moved parallel to the axis of the cylinder. , increments the cylinder angularly after each pass of the head to move the plate The image above can also be made to grow circumferentially. Write to plate The angular position of the head is monitored by the controller as described above, and its Distance detection and adjustment mechanism (described in co-pending U.S. Patent Application No. 553,817) ) controls the distance the head is away from the plate.

The power of the arc actually reaching the plate (i.e. its voltage/current profile) is the inherent breakdown voltage associated with the surrounding air or applied working gas, the electrode or The voltage of the pulse (positive or negative) applied to the lasma jet source and the rise of this pulse. It depends on the rise time. The interaction of these variables causes breakdown and arcing to occur instantaneously. It follows from the fact that it is not an intermediate process. The drop in resistance associated with yield is typically This prevents the voltage from sustaining above the threshold, but the rise time is very fast. If the gap is crossed and this threshold is Voltage levels above the low value can be imposed for short periods of time.

On the other hand, the range of current depends on both this effective arc voltage and the design of the pulse circuit. ing. Furthermore, the electrical properties of the plates can limit the maximum useful current. be. This is because the conductivity is insufficient (e.g. for a given current level (by using too many layers of material), the result is a build-up of charge that is This is because it reduces the strength of arcs or prevents arcs altogether. In the present invention The preferred applied voltage level, i.e. the electrode or plasma jet rather than the effective arc voltage. The actual voltage supplied to the power source is in the range of 1000 to 5000 volts. Ru. Potential levels above 2000 ports are particularly preferred. As mentioned earlier, the place The effective arc voltage for a given applied voltage is the rise time of the voltage pulse, and It depends on the breakdown voltage of the surrounding air or the applied working gas. In the present invention The preferred operating current range is 0.1 to 1 amp. The low current level is It tends to be associated with easily ionizable gases such as argon, and has high current levels. Bell tends to be associated with gases that have higher breakdown voltages, such as air.

the applied voltage or current supplied to the electrode, or the duration of its application, or By varying the number of discharges applied to the position, images of variable magnitude can be created. can generate a medium-sized spot.

Means for accomplishing this are well known in the art. Similarly, each image point The dot size can be changed by repeatedly energizing the electrode with pulses at the point. The final dot size is determined by the number of applied pulses (pulses count modulation).

Preferred embodiments of the invention designed for use with this type of imaging device The plate structure is described in U.S. Patent No. 4,911,295 and U.S. Patent Application No. 07/442. No. 317 and No. 07/410295. Simply put, these The plate minimally includes a conductive metal layer and a second layer below this metal layer. However, the metal layer and the underlying layer have different affinities for ink and/or water. spark release The electric current is powerful enough to remove the metal layer, thereby selecting the underlying layer. Expose at selected locations. Once the scan is complete, the selections collectively This will create a strong image.

In a modification of this structure, suitable for dry printing, the plates are oleophobic (e.g. a first layer of metal (recone); a second layer of metal underneath this first layer; and a lipophilic third layer below the layer. Image of this type of plate The spark discharge removes both the top layer and the metal layer, but the bottom Leave the layers intact.

Using a metallic imaging layer offers two key advantages. The first is , high imaging accuracy. In non-contact imaging systems, The accuracy of the manufacturing process is determined by the wandering of the discharge as it moves from its source to the surface of the plate. It depends on the performance to prevent. This generally means that the plate to be imaged is A large electric field gradient is required between a point on the ground and the discharge source. The discharge is the strongest The part of the plate where the electric field is strongest is exactly opposite the discharge source. Occurs in certain places. However, overcoming the inherently random nature of the discharge Therefore, the strength of the electric field at this location is greater than the strength at any other location. must also be thick enough (the greater the slope, the more the path from the source to the plate The electric field strength weakens quickly when deviates from the normal value. Therefore high power The discharge generates a strong gradient, which is a predominant force in all directions away from the normal one. By emphasizing the recessiveness of the electric field strength, it is advantageous for a straight discharge path.

Second, high-energy discharges can erode refractory materials. strong surface The use of layers and substrate layers provides a longer operating life than that of the prior art. lithographic printing plates can be produced.

3. Sukedono's amount of fraud To operate the press in imaging mode, the operator must first The plate series used to print the blank into the finished document Attach it to each of the terminals. The operator then identifies the color separations of the original to be reproduced. A disk, tape or other form of digital storage that carries digital data. Insert the storage medium and load the data into the internal memory of the computer 40. Operation The printer retrieves the data and previews the image on the display 46 before printing. can be divided into minutes. At the operator's command, the computer 40 The image signals representing the digital data are sent to the controllers 30a, 30b, 30c and 30. d, and these activate the write heads of the associated imaging system. and thus the corresponding image on each plate cylinder. Applies to plates.

Alternatively, the printing computer 40 may include a preprint editing system such as Rusk image processing. raw image data and text data (later (typically encoded in a page description language) as an image signal. convert it into a bitmap ready for output, which is sent to the controller. this The ability to bring almost all manufacturing steps prior to actual output and publication into the printing machine The result is a truly integrated digital printing system. It will be done. The pre-print editing feature “sifts” image data into halftone patterns. minutes, and their patterns and encoded text information (e.g. character files). Generate a bitmap from (specifying font, scaling, and text alignment) Operators can directly input information from basic rask image processing to operations. It is possible to range up to full editing capabilities that allow you to Ko Computer 40 performs these tasks when not occupied by imaging tasks. What functions does printing perform? For example, typical imaging speeds are The computer 40 is much slower than the maximum speed it can operate at. “Multitasking” with imaging of one plate and pre-print operations of another plate It can be carried out.

After the plate has been imaged (or off-board plate imaging and (followed by loading the imaged plate into the plate cylinder) , the printing press can be operated in print mode to print proofs of the original.

The number is determined by operator commands entered from the keyboard 48. . If the colors printed on the print are acceptable, the operator You can issue commands to the machine to print the required number of final prints. change If necessary, create a new printing plate with the appropriate corrected image data. can be created.

Each plate cylinder is automatically advanced around the plate cylinder , a plate containing a length of imageable flexible mat or film Place a new longitudinal set of mat or film in such a way as to accommodate a cassette of material. It is also possible for the component to be arranged on the cylinder surface. like this produce plates with satisfactory, well-aligned images very quickly. can be generated efficiently. Old images are given new materials At the same time, it is rolled up inside the plate cylinder.

4. This printing machine suffers from various forms of periodic mechanical problems such as axial misalignment and skew. Includes means for correcting mechanical errors. First alignment correction system of the present invention operates during imaging of the plate. At this point, the plate It is necessary to maintain angular harmony between the cylinders, and similarly placed images so that the image spot is applied at a consistent circumferential location on each cylinder. be made into This means that each individual plate imaging system body plate cylinder (holding the plate to be imaged) and each other. It is necessary to harmonize both.

In the center-imaging embodiment of the invention, such matching is achieved automatically. Na The image cylinder drives each plate cylinder, and all plates It is possible to determine the angular position of the cylinder with reference to the gear segment of the impression cylinder. This is because it is Noh. In the case of an in-line embodiment, imaging is started. Establish a position on each plate with the writing head facing this position. and the spatial relationship between the write head and its associated plate cylinder. It is necessary to maintain the relationship constant, thus fixing a particular image spot location. The identifying image signals image the same physical location on each plate. caused to occur. The inventors have implemented this in such a way that each plate cylinder Each controller 30a, 30b rotates with the same, consistent angular velocity.

30c and 30d with angle encoders (proper design for which is technically sufficient) This is achieved by including (characterized in minutes).

A computer 40 coupled to each of the controllers controls the associated angle encoder. It receives the output of the plate cylinder and uses appropriate control signals to ensure a consistent alignment between the plate cylinders. Ensure consistent rotation and angular harmony. Establish a consistent starting position and to correct alignment errors caused by factors other than misalignment. To do this, computer 40 maintains a dot position index table for each station. (included in the CPU 44 or each of the controllers 30a, 30b, 30c, and 30d) have access to This index table should be imaged. Stores the X and Y axes of all dot positions in the image. A simple test pattern ( so-called edges using plates imaged with e.g. vertical and horizontal lines) The printed material is printed by performing a cross-through test. specific color la If the in deviates from the theoretical true position, measure the difference and set the appropriate y offset into the index table and the index corresponding to the deviation dot of that particular color. Enter at a position within the table. This calibration process is the final inspection step in printing press manufacturing. The dots are executed only once in the factory for each floor and are modified for each color. The computer 40 or each Permanently stored in that controller. Performing a similar calibration later on the printing press In situations where certain parts of the machine, such as gear mechanisms or cylinders, have to be replaced, only required.

FIG. 2 shows a printing station 30c printing, for example, a cyan image Ic. , for example, by printing station 30d printing yellow image Iy. A two-color print P is shown. Plate cylinders 24c and 24 Since d are out of phase with each other, the yellow image is used as a position reference. Displaced in the axial direction (X direction) and circumferential direction (X direction) with respect to the cyan image Ic. (i.e. not aligned). Therefore, the starting positions of each image can be It is necessary to match the

The yellow image is also subject to skew and, for example, the plate cylinder 24 Since the diameter of d is slightly longer than that of the plate cylinder 24c, it is longer. ing. Assuming that the image is scanned circumferentially as in Fig. , the plate cylinder 24d has a slightly larger diameter than the plate cylinder 24c. Even if the image dots formed on the plate about the yellow color are than the corresponding dot imaged on the cyan plate in section 30c. They are spaced more apart along the scan line, thus creating a yellow image. It will be longer than the cyan image.

Corresponding targets for different color images (e.g. image corners or aiming crosshairs) ), by introducing appropriate x and y offsets, the station The yellow image formed at station 30d is formed at station 30c. can be matched with the standard cyan image. Therefore, in Figure 2, Vertical of upper left corner 1c and ly (or equivalent aiming crosshair) of images Iy and Ic The distance between the perpendicular lines is optically measured and sent to the CPU 44 using the keyboard 48. and input an appropriate offset in the minus X direction, and the controller 30d The writing head of writing system 42d is controlled to write along plate cylinder 24d. write earlier, i.e., closer to its home position, on the travel path You can make it start. Prints made from modified plates (i.e. a print similar to that shown in Figure 2), the corner 1y and the vertical direction of the IC. Repeat this step until the lines match.

A similar procedure is used to achieve alignment in the X direction. this In this case, compare the horizontal lines of corners 1y and 1c of printed images Iy and Ic. , enter some desired offset (plus y offset in this case) on the keyboard. input to the controller 14 via the card 48. Controller 30d then The writing head of imaging system 42d writes a yellow image to it. to start earlier in the rotation of the plate cylinder at the station of make it happen. As well as the offset in the X direction, the angle 1 of the images Iy and Ic Image the modified plate until the horizontal line positions of y and 1c overlap. A corrected print P is created by editing.

If one image is longer than the other, as shown in Figure 2, , the horizontal lines of the lower left corners 2y and 2c (or equivalent targets) become misaligned? That becomes clear.

A computer that measures the difference and outputs an appropriate signal to the relevant controller. Modifications are made by entering the appropriate modifications at 40. Thus, in Figure 2 In order to correct the excessive length of the image Iy, the computer 40 By inputting the pulse count offset to the controller 30d, each scan line in the circumferential direction is From this count, one or subtract more timing pulses; add more than one pulse; If it is necessary to delete such additions or deletions, such additions or deletions must be made uniformly along the scan line. are widely distributed and therefore generally occur only occasionally.

For example, the skew error due to the taper of the cylinder is at the top right of images Iy and Ic. Compare the horizontal lines of angles 3y and 3c to find the phase angle of the plate cylinder. By starting the scan lines progressively earlier or later, more or less similar It can be modified in any way. Thus, for example in FIG. The scan lines are started progressively earlier to reduce the skew between images Iy and Ic. will be corrected.

The following dot position correction or offset is sent to the computer 4o (or directly to the computer). controllers 30a, 30b, 30c and 3od), then the print The printing press contains the dot pattern for each plate cylinder in the index table. Then, the location of all dot positions (i.e., the write signal to the write head) timing) is known.

At the beginning of each scanning motion that writes an image on the plate, the dot The pattern consists of each controller cycling at the same rate as the plate cylinder rotates. Downloaded into the troller's circular memory. The write head is The controller or computer 40 receives the image signal and dot position or write signal. is activated or discharged when both are supplied to the write head at the same time. write message If there are fewer timing pulses between signals, the head will be at the beginning of the image signal. Discharge is performed closer, resulting in earlier head discharge than normal. Become. If there are more timing signals between the write signals, the head will discharge closer to the end of the signal, resulting in a delayed discharge of the head. Become.

When a printing press prints web material, it must maintain print alignment to the recording material. In order to can be entered. For example, increasing or decreasing the speed at which the plate cylinder rotates. , thereby changing the relative image phase of each cylinder. be able to. Alternatively, sliding tracks can be used to adjust the distance between each other. It is also possible to provide the printing station itself on the The web transport system can also be configured to allow for varying travel lengths. Wear. Both methods facilitate coarse or fine adjustment of the time between successive impressions. , thereby changing the relative phase of these impressions, and This can be controlled using a dot index approach as described above.

5 Ink-bi The operator also inspected the image on the print during the printing process. As a result, if you deem it advisable, you can use the keyboard 48 to The flow of ink at the station can be adjusted. Furthermore, C.P. Program U44 to spray ink along each ink-jetting doctor blade. automatically controlling the regulating regulator (e.g. screw or key); Printing in bands controlled by each adjusting screw or key the required amount of ink across the image based on the count of the number of dots of each color You can set the screw or key according to the quantity.

If desired, the printed material may be printed in the outer margins of the desired image area. can include colored bars. These margins are removed after the print is created. removed. Such colored bars are the bottom merge of print 102 in FIG. It is shown at 108 in the section. This color bar is usually cyan (C), for example. , yellow (y), magenta (m), and black (b) color blocks, the printing machine shows the colors printed by each printing station across the width of the .

In fact, the bar 108 in the two-color print shown in Figure 1-1 is cyan (C) and yellow. It has only blocks (y). This bar also shows color gradient, resolution, etc. It can also include blocks with geometric patterns.

” in duplicate, and as in the aforementioned U.S. Pat. No. 4,058,058, Printing press 10 typically includes multiple electronically controlled inputs distributed throughout the press. can have an adjustment screw or key so that each print station The ink ejector at the station is connected to the plate cylinder at that station. the amount of ink applied. Figure 2 shows cyan ink. juxtaposed to print 102 at print station 15c for adjustment. Six sets of such keys are shown. In actual implementation, typical printing The machine has more keys at each station. For example, 18 inches (460 The printing press has 16 imprints in each of stations 15a to 15d. may have a link key. Computer 40 provides a printer for each print station. Determine which scan line of rate is associated with each ink key. example For example, line 1-100 = key 1, line 101-200 = key 2, etc. Ru. If the print is narrow, some keys may not be used.

Computer 40 then determines the number of image dots associated with each key. and calculate the coverage percentage for that key. This is per ink key defined as the total dot count divided by the maximum dot count per ghee. be justified. The latter amount applies to all scan lines assigned to a given ink key. If all dots are printed, the ink key represents the total number of dots that can be drawn. Computer 40 then: Convert this percentage to a key setting and then adjust the key solenoid to achieve that setting. Control appropriately. Detecting the image I or color bar 108 printed on the printed matter indicates that color correction at any ink key position is justified when If so, this correction can be made via keyboard 48.

Optionally, add a densitometer for fully automated closed-loop It is possible to achieve a color adjustment system. Ink adjustment screw or key 1 The initial setting of 06 is performed by the computer 40 as described above. und-based (can be used for "on-the-fly" flash color density) The meter allows you to scan different colors (within the color bar 108) and The results can be fed back to the CPU 44. The CPU 44 then Compare the densitometer readings against the original dot count analysis and If necessary, make new key adjustments. The CPU 44 also reads the densitometer. It can be programmed to correlate values and color correction levels over time. This thing is , it is easy to "adaptive learn" the optimal correction level for different ink coverage areas. This can be done by computer 40 without the need for constant operator attention. can be directly implemented. Preferably, computer 40 also selects is programmed to allow manual assistance with color correction levels.

A densitometer, such as that shown at 110 in FIG. 2, is installed at the outlet end of the printing press. , for example, using a servo-controlled lead screw to position the color block of color bars 108. correspondingly, it can be positioned at selected positions across the width of the printing press.

The densitometer flashes the moment the colored bar 108 is on the underside of the densitometer. It is operated like a flash. In this way, the device can block the color of bar 108. can read the amount of color in the screen. The solid phase density of each color is determined by the required density. maintained at meter level. Instrument 110 readings are low for a particular color If the appropriate ink key at the corresponding print station is to correct this error. If the reading is high, check the exact Close the offending key the required amount to recover the densitometer reading. It will be done. These steps can be repeated as many times as necessary.

Once the process is complete, the data ( for each printing station). This color system or fingerprint ( salient features) can then be used to set up the next print job. Wear. By using this technique, each subsequent job will start with the final It will be closer to the setting.

Computer 40 also performs other normal printing press operations such as starting, shutting down, and cleaning. Can be programmed to automatically control operation.

(So that the above objectives, especially those clarified from the above explanation, can be achieved efficiently) Let us see what is accomplished. Also, without departing from the scope of the invention, How to carry out the method described and make certain changes in the structure described above Therefore, all matters contained in the above description or the attached drawings All matters set forth are to be construed in an illustrative and not in a limiting sense. It is intended that the Furthermore, the following claims cover the invention as described herein. may be intended to encompass all of the general and specific characteristics of should be understood.

FIG. 2 Copy and translation of written amendment> Submission (Article 184-7, Paragraph 1 of the Patent Act) July 9, 1993 Day precept

Claims (94)

[Claims] 1. a. A plate cylinder that supports the printing plate and the image against the plate. at least one discharge source applied and said at least one discharge source applied during rotation of the plate cylinder. also preload each discharge source such that one discharge source scans a raster over the plate surface. at least one print station each including means for moving relative to the print cylinder; and b. means for rotating each cylinder; and c. responds to electronic signals representing the original , the discharge source forms an image consisting of dots corresponding to the original on the plate surface control means for instantaneously controlling and activating the discharge source during scanning of the discharge source so that the discharge source and the control means controls the x-axis and the x-axis of substantially all dot positions on the plate. It includes a dot position index table for storing the y-axis and the electronic signal exists. If there is an image dot at the dot position selected from the dot positions. configured to activate the discharge source to form a discharge source; Printing device. 2. In order to shift the x-axis and y-axis of the dot position on the plate, Claim 1 further comprising means for applying a position offset signal to said control means. equipment. 3. further comprising means for varying the length of the scan to adjust the circumferential dimension of the image. , the apparatus of claim 2. 4. Contains multiple printing stations, images produced by each plate The x and y axes of the dot positions on each plate are shifted and each printing station further indicates the angular position of the plate cylinder. detecting means coupled to the plate cylinder for generating an angular position signal; integrated all control means to achieve angular alignment between the plate cylinders. The apparatus of claim 2 further comprising means coupled to all detection means for maintaining Place. 5. Claim further comprising means for sequentially transferring the recording medium between printing stations. 4 device. 6. Contains multiple printing stations, images produced by each plate The x and y axes of the dot positions on each plate are a means for transferring the web of recording material between printing stations; Movement of the print station relative to the recording material to maintain alignment of the print onto the material. 3. The apparatus of claim 2, further comprising means for integrating operations. 7. The integrating means increases or retards the rotational speed of each plate cylinder. 7. The apparatus of claim 6, comprising: 8. The integrating means comprises means for adjusting the travel length of the web between printing stations. 7. The apparatus of claim 6. 9. 2. The apparatus of claim 1, wherein each discharge source is a spark discharge electrode. 10. 2. The apparatus of claim 1, wherein each discharge source is a plasma jet. 11. 2. The apparatus of claim 1, wherein each discharge source is a laser. 12. 2. The apparatus of claim 1, wherein each discharge source is a non-laser source of electromagnetic radiation. 13. 2. The apparatus of claim 1, wherein each discharge source is an inkjet. 14. a. In response to ink control signals at each print station, An option to adjust the amount of ink applied to the plate on the plate cylinder of the machine. a. link adjusting means; and b. an input for supplying an ink control signal to the regulating means; control means for controlling a print station by each print station on selected locations of said plate; In addition to counting the number of image dots to be formed, the printing station based on the number of dots to be printed by the printing station. and an ink control means for controlling said ink adjustment means in said ink adjustment means. Apparatus according to claim 1. 15. a. Color densitometry for detecting colors in printed matter printed by printing equipment data means; b. The readings of the densitometer means are recorded as dot counters for each printing station. means for generating a color correction signal for the station; and c. applying the correction signal to the control signal and applying it by the ink adjustment means; 14. The printing apparatus of claim 13, further comprising means for adjusting the amount of ink applied. 16. Each ink regulating means in each printing station is The image applied to different circumferential areas of the plate on the plate cylinder in the A plurality of electrically energized inputs spaced across the device to regulate the amount of ink. the setting of each key at each station is at least partially printed on the corresponding area of the printing plate at the printing station in question. 15. The apparatus of claim 14, wherein the number of image dots is determined by the number of image dots. 17. A color correction signal is applied to the ink control means, and the settings of the keys are set as described above. the adjustment key so that it deviates from the position determined by the image dot count. 17. The apparatus of claim 16, further comprising means for varying an ink control signal for the ink control signal. 18. A color densitometer that detects the colors in printed matter printed by a printing device 18. The apparatus of claim 17, further comprising means. 19. Each ink regulating means in each printing station is The image applied to different circumferential areas of the plate on the plate cylinder in the A plurality of electrically energized inputs spaced across the device to regulate the amount of ink. each ink regulator at each station. The settings are determined by comparing the reading of the densitometer means with a predetermined concentration level. 20. The apparatus of claim 18, wherein: 20. The device includes at least one printing station for imaging the plate. 2. The printing device according to claim 1, further comprising two printers. 21. The device has cyan, magenta, yellow, and black colors for plate imaging. 21. Printing according to claim 20, having at least four printing stations for printing colors. Device. 22. The image of the plate can be adjusted so that the machine prints the same color or two different colors in two densities. 21. The printing apparatus of claim 20, having at least two printing stations for printing. Place. 23. At least one printing station is configured to apply spot lacquer. 21. The printing device according to claim 20. 24. Further includes a back printing means for reversing the orientation of the recording medium between printing stations. 22. The printing device of claim 21, comprising: 25. a. A plate cylinder that supports the printing plate and the image against the plate. at least one discharge source applied and said at least one discharge source applied during rotation of the plate cylinder. also preload each discharge source such that one discharge source scans a raster over the plate surface. at least one print station each including means for moving relative to the print cylinder; and b. means for rotating each cylinder; c. At each printing station In response to the ink control signal, the plate on the plate cylinder of the station concerned is an ink regulating means for regulating the amount of ink applied to the ink; and d. said adjusting hand an ink control means for supplying an ink control signal to the plate; Counts the number of image dots to be formed by each print station on the selected location. and printing by the printing station on selected locations of the plate. The ink adjusting means is controlled at the printing station based on the number of dots to be produced. and an ink control means to control the Printing device. 26. Each ink regulating means in each printing station is The image applied to different circumferential areas of the plate on the plate cylinder in the A plurality of electrically energized inputs spaced across the device to regulate the amount of ink. each ink regulator at each station. The settings of the printing plate are at least partially 26. The apparatus of claim 25, wherein the number of image dots printed in a corresponding area Place. 27. Applying a color correction signal to the ink control means and adjusting the settings of the regulator. the position determined by the image dot count. Claim 26 further comprising means for varying the ink control signal to the regulator. equipment. 28. The device includes at least one printing station for imaging the plate. 26. The printing device according to claim 25, further comprising two printers. 29. The device has cyan, magenta, yellow, and black colors for plate imaging. 29. Printing according to claim 28, having at least four printing stations for printing colors. Device. 30. The image of the plate can be adjusted so that the machine prints the same color or two different colors in two densities. 30. The printing apparatus of claim 29, comprising at least two printing stations for printing. Place. 31. At least one printing station is configured to apply spot lacquer. 29. The printing device according to claim 28. 32. further comprising reverse printing means for reversing the recording medium between printing stations; The printing device according to claim 28. 33. 26. The apparatus of claim 25, wherein each discharge source is a spark discharge electrode. 34. 26. The apparatus of claim 25, wherein each discharge source is a plasma jet. 35. 26. The apparatus of claim 25, wherein each discharge source is a laser. 36. 26. The apparatus of claim 25, wherein each discharge source is a non-laser source of electromagnetic radiation. 37. 26. The apparatus of claim 25, wherein each discharge source is an inkjet. 38. Claim further comprising means for sequentially transferring the recording medium between printing stations. The device of item 25. 39. means for transferring the web of recording material between printing stations; Coordinates the operation of the print station relative to the recording material to maintain print consistency on the recording material. 26. The apparatus of claim 25, further comprising means for matching. 40. The integrating means increases or retards the rotational speed of each plate cylinder. 40. The apparatus of claim 39, comprising stages. 41. The integrating means comprises means for adjusting the web travel length between the printing stations. 40. The apparatus of claim 39. 42. a. plate cylinder, b. a first layer of metal having a printed surface and a second layer underlying the first layer; and wherein the first and second layers are a printing liquid selected from the group consisting of water and ink. printing plates having different affinities for; c. means for mounting said plate relative to a plate cylinder; d. The printing surface Spatial spark discharge across the printed surface between closely spaced electrodes and the plate removing said first layer of metal at selected locations on the plate exposed to means for exposing the second layer; e. The electrode is relative to the plate cylinder in order to scan the printing surface with the electrode. means for moving; and f. Spark discharge occurs a selected number of times during a scan controlling the spark discharge in accordance with an electronic signal representing the image; An array of inkable image spots is placed on a plate to create a printed product. consisting of a means for directly generating Printing device. 43. 43. The apparatus of claim 42, wherein the spark discharge carries a current of at least 0.1 ampere. Place. 44. 43. The apparatus of claim 42, wherein the potential of the spark discharge exceeds 2000 volts. 45. A potential is established by applying a positive voltage to the electrode with respect to the plate 45. The apparatus of claim 44. 46. A potential is established by applying a negative voltage to the electrode with respect to the plate 45. The apparatus of claim 44. 47. The potential of the spark discharge is such that the spark discharge is substantially direct from the electrode to the printing surface. 43. The apparatus of claim 42, wherein the apparatus is sufficient to produce a linear movement. 48. In order to change the size of the spot generated by the discharge, the voltage varying characteristics selected from the group consisting of current, length of time, and number of spark discharges; 43. The apparatus of claim 42, further comprising means. 49. a. plate cylinder, b. an oleophobic first layer having a printed surface and a metallic second layer underneath the first layer; a printing plate comprising a second layer and an oleophobic third layer below the second layer; c. means for mounting said plate relative to a plate cylinder; d. The printing surface Spatial spark discharge across the printed surface between closely spaced electrodes and the plate removing said first and second layers at selected locations on the plate exposed to means for exposing the third layer; e. The electrode is relative to the plate cylinder in order to scan the printing surface with the electrode. means for moving; and f. Spark discharge occurs a selected number of times during a scan controlling the spark discharge in accordance with an electronic signal representing the image; An array of inkable image spots is placed on a plate to create a printed product. and a means for directly generating Printing device. 50. 50. The apparatus of claim 49, wherein the spark discharge carries a current of at least 0.1 amps. Place. 51. 50. The apparatus of claim 49, wherein the potential of the spark discharge exceeds 2000 volts. 52. A potential is established by applying a positive voltage to the electrode with respect to the plate 52. The apparatus of claim 51. 53. A potential is established by applying a negative voltage to the electrode with respect to the plate 52. The apparatus of claim 51. 54. The potential of the spark discharge is such that the spark discharge is substantially direct from the electrode to the printing surface. 50. The apparatus of claim 49, wherein the apparatus is sufficient to produce a linear movement. 55. In order to change the size of the spot generated by the discharge, the voltage varying characteristics selected from the group consisting of current, length of time, and number of spark discharges; 50. The apparatus of claim 49, further comprising means. 56. An apparatus for imaging a phosphorographic printing plate, the apparatus comprising: a. a ring layer having a printed surface and comprising a metal layer and a second layer underlying the metal layer; means for supporting a printing plate, and wherein said metal layer and said second layer are free from water and ink; having different affinities for printing liquids selected from the group consisting of; b. Each at least one spark discharge source including a write head comprising electrodes; c. means for positioning the discharge source near the printing surface; and d. for each electrode A high voltage pulse of over 2,000 volts is applied to bring the printing surface into contact with the nozzle. means for producing a spark discharge substantially perpendicular to the printed surface without the electrical discharge removes the metal layer and exposes the second layer at selected locations; of sufficient strength to make the printing surface resistant to the liquid at the location. A device consisting of changing the compatibility. 57. 57. The device of claim 56, wherein the spark discharge carries a current of at least 0.1 ampere. Place. 58. A potential is established by applying a positive voltage to the electrode with respect to the plate 57. The apparatus of claim 56. 59. A potential is established by applying a negative voltage to the electrode with respect to the plate 57. The apparatus of claim 56. 60. The potential of the spark discharge is such that the spark discharge is substantially direct from the electrode to the printing surface. 57. The apparatus of claim 56, wherein the apparatus is sufficient to produce a linear movement. 61. In order to change the size of the spot generated by the discharge, the voltage varying characteristics selected from the group consisting of current, length of time, and number of spark discharges; 57. The apparatus of claim 56, further comprising means. 62. An apparatus for imaging a phosphorographic printing plate, the apparatus comprising: a. an oleophobic first layer having a printed surface and a metallic second layer underneath the first layer; a phosphorographic printing printer comprising a second layer and a third lipophilic layer below the second layer. means to support the rate; b. at least one spark discharge source each including an electrode; c. Discharge source of printing surface means for proximate positioning; and d. Over 2000 volts for each electrode A high voltage pulse is applied to the printed surface without the surface coming into contact with the nozzle. means for producing a spark discharge substantially perpendicular to the selected location; at a strength sufficient to remove said first and second layers to expose said third layer. A device consisting of degrees. 63. 63. The apparatus of claim 62, wherein the spark discharge carries a current of at least 0.1 amps. Place. 64. A potential is established by applying a positive voltage to the electrode with respect to the plate , the apparatus of claim 62. 65. A potential is established by applying a negative voltage to the electrode with respect to the plate , the apparatus of claim 62. 66. The potential of the spark discharge is such that the spark discharge is substantially direct from the electrode to the printing surface. 63. The apparatus of claim 62, wherein the apparatus is sufficient to produce linear movement. 67. In order to change the size of the spot generated by the discharge, the voltage varying characteristics selected from the group consisting of current, length of time, and number of spark discharges; 63. The apparatus of claim 62, further comprising means. 68. a. at least one plate cylinder; b. at least one having a printed surface; a printing plate; c. Hands for installing each plate in the plate cylinder step and d. Bringing a discharge to a selected location on each plate, causing a discharge at said location. the affinity of the printing plate for a printing liquid selected from the group consisting of water and ink; at least one imaging means for changing the e. 1) Electronically encoded documents consisting of image and text data rasterize the image into a bitmap ready for output, and 2) Indicate the plate position where the imaging discharge should be applied according to the bitmap. a computer that generates control signals; f. Each imaging means and play means for relatively moving the cylinders to scan each printing cost surface; as well as g. In response to the control signal, the discharge occurs on the plate position corresponding to the bitmap. and control the imaging discharge to generate ink-filled copies of the document. means for producing an array of imageable spots directly on each plate; A printing device consisting of: 69. a plate cylinder supporting a printing plate, the plate being a printing surface; a first layer having a surface and made of metal; and a second layer below the first layer; For printing liquids in which the first and second layers are selected from the group consisting of water and ink. A method of imaging on printing presses with different affinities, the method comprising: a. mounting said plate on a plate cylinder; b. in contact with the printed surface. between an electrode closely spaced to said printed surface and said plate without touching; The printed surface is exposed at selected locations on the plate to protect against spark discharges. removing the first layer of metal to expose the second layer at selected locations on the plate; a step of c. The electrode and plate cylinder are moved relative to each other to allow the electrode to scan the printing surface. performing, and d. The image is set so that the spark discharge occurs a selected number of times during the scan. The spark discharge is controlled according to an electronic signal representing the electric signal, and the spark discharge is controlled according to an electronic signal representing the electric signal. Print an array of inkable image spots to create a replica of the document. A method consisting of the step of generating directly on the rate. 70. 70. The spark discharge of claim 69, wherein the spark discharge carries a current of at least 0.1 ampere. Law. 71. 70. The method of claim 69, wherein the potential of the spark discharge exceeds 2000 volts. 72. A potential is established by applying a positive voltage to the electrode with respect to the plate 72. The method of claim 71. 73. A potential is established by applying a negative voltage to the electrode with respect to the plate 72. The method of claim 71. 74. The potential of the spark discharge is such that the spark discharge is substantially direct from the electrode to the printing surface. 70. The method of claim 69, wherein the method is sufficient to cause linear movement. 75. In order to change the size of the spot generated by the discharge, the voltage varying characteristics selected from the group consisting of current, length of time, and number of spark discharges; 70. The method of claim 69, further comprising the step. 76. a plate cylinder and a printing plate on the plate cylinder for printing; a first layer having a surface and being oleophobic, and a second metal layer below the first layer. and a third lipophilic layer below the second layer. A method of imaging on a printing press comprising: a. the plate mounting the plate cylinder; b. without contacting the printed surface; for a spark discharge between an electrode closely spaced on the printing surface and the plate; Expose the printing surface at selected locations on the plate and apply it to the selected locations on the plate. removing the first and second layers to expose the third layer; c. The electrode and plate cylinder are moved relative to each other to allow the electrode to scan the printing surface. performing, and d. The image is set so that the spark discharge occurs a selected number of times during the scan. The spark discharge is controlled according to an electronic signal representing the electric signal, and the spark discharge is controlled according to an electronic signal representing the electric signal. Print an array of inkable image spots to create a replica of the document. A method consisting of the step of generating directly on the rate. 77. 77. The spark discharge of claim 76, wherein the spark discharge carries a current of at least 0.1 ampere. Law. 78. 77. The method of claim 76, wherein the potential of the spark discharge exceeds 2000 volts. 79. A potential is established by applying a positive voltage to the electrode with respect to the plate , the method of claim 78. 80. A potential is established by applying a negative voltage to the electrode with respect to the plate , the method of claim 78. 81. The potential of the spark discharge is such that the spark discharge is substantially direct from the electrode to the printing surface. 77. The method of claim 76, wherein the method is sufficient to cause linear movement. 82. In order to change the size of the spot generated by the discharge, the voltage varying characteristics selected from the group consisting of current, length of time, and number of spark discharges; 77. The method of claim 76, further comprising the step. 83. a printing print having a printing surface and comprising a metal layer and a second layer underlying the metal layer; 2. A method for imaging rate, wherein the metal layer and the second layer are having different affinities for printing liquids selected from the group consisting of: and the method comprises: a. at least one writing head each comprising an electrode; The spark discharge source is spaced apart from the printing surface, and each write head is placed facing the printing surface. orienting; and b. High voltage power supply exceeding 2000 volts for each electrode to the print surface without contacting the print head with the writing head. and generating a substantially vertical spark discharge, wherein said discharge is directed toward said metal layer. of sufficient strength to remove the second layer to expose the second layer at selected locations; by changing the affinity of the printing surface for the liquid at the location; How to become. 84. 84. The spark discharge of claim 83, wherein the spark discharge carries a current of at least 0.1 ampere. Law. 85. A potential difference is established by applying a positive voltage to the electrodes with respect to the plates. 84. The method of claim 83. 86. A potential difference is established by applying a negative voltage to the electrodes with respect to the plates. 84. The method of claim 83. 87. A potential difference substantially increases the spark discharge from the writing head to the printing surface. 84. The method of claim 83, wherein the method is sufficient to produce a straight line movement. 88. In order to change the size of the spot generated by the discharge, the voltage a characteristic selected from the group consisting of flow, length of time, and number of plasma jet discharges; 84. The method of claim 83, further comprising the additional step of varying. 89. a first layer having a printed surface and being oleophobic; and a metallic layer underneath the first layer. A printing plate comprising a second layer and an oleophilic third layer below the second layer is prepared. A method of imaging, the method comprising: a. Impress at least one spark discharge source each including a writing head consisting of an electrode. spaced from the printing surface and orienting each writing head facing the printing surface; , and b. A high voltage pulse of over 2000 volts is applied to each electrode, Drops substantially against the printing surface without bringing the printing surface into contact with the writing head. generating a direct spark discharge, said discharge selecting said first and second layers. strong enough to be removed at selected locations to expose said third layer; How to become. 90. 90. The spark discharge of claim 89, wherein the spark discharge carries a current of at least 0.1 ampere. Law. 91. A potential difference is established by applying a positive voltage to the electrodes with respect to the plates. 90. The method of claim 89. 92. A potential difference is established by applying a negative voltage to the electrodes with respect to the plates. 90. The method of claim 89. 93. A potential difference substantially increases the spark discharge from the writing head to the printing surface. 90. The method of claim 89, wherein the method is sufficient to cause linear movement. 94. In order to change the size of the spot generated by the discharge, the voltage a characteristic selected from the group consisting of flow, length of time, and number of plasma jet discharges; 90. The method of claim 89, further comprising the additional step of varying.